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Aoyama J, Saito Y, Matsuda K, Tanaka T, Kamio K, Gemma A, Seike M. Increased CTGF expression in alveolar epithelial cells by cyclic mechanical stretch: Its mechanism and the therapeutic effect of pirfenidone. Respir Physiol Neurobiol 2023; 317:104142. [PMID: 37625675 DOI: 10.1016/j.resp.2023.104142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/12/2023] [Accepted: 08/20/2023] [Indexed: 08/27/2023]
Abstract
The mechanisms of fibrosis onset and development remain to be elucidated. However, it has been reported that mechanical stretch promotes fibrosis in various organs and cells, and may be involved in the pathogenesis of pulmonary fibrosis. We demonstrated that ventilator-induced lung hyperextension stimulation in mice increased the expression of connective tissue growth factor (CTGF), a profibrotic cytokine, in lung tissue. Increased CTGF expression induced by cyclic mechanical stretch (CMS) was also observed in vitro using A549 human alveolar epithelial cells. Pathway analysis revealed that the induction of CTGF expression by CMS involved MEK phosphorylation. Furthermore, early growth response 1 (Egr-1) was identified as a transcription factor associated with CTGF expression. Finally, the antifibrotic drug pirfenidone significantly reduced CTGF expression, MEK phosphorylation, and Egr-1 levels induced by CMS. Thus, our results demonstrated that profibrotic cytokine CTGF induced by CMS may be a therapeutic target of pirfenidone.
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Affiliation(s)
- Junichi Aoyama
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
| | - Yoshinobu Saito
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan.
| | - Kuniko Matsuda
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
| | - Toru Tanaka
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
| | - Koichiro Kamio
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
| | - Akihiko Gemma
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
| | - Masahiro Seike
- Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603 Tokyo, Japan
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2
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Nizamoglu M, Joglekar MM, Almeida CR, Larsson Callerfelt AK, Dupin I, Guenat OT, Henrot P, van Os L, Otero J, Elowsson L, Farre R, Burgess JK. Innovative three-dimensional models for understanding mechanisms underlying lung diseases: powerful tools for translational research. Eur Respir Rev 2023; 32:230042. [PMID: 37495250 PMCID: PMC10369168 DOI: 10.1183/16000617.0042-2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/04/2023] [Indexed: 07/28/2023] Open
Abstract
Chronic lung diseases result from alteration and/or destruction of lung tissue, inevitably causing decreased breathing capacity and quality of life for patients. While animal models have paved the way for our understanding of pathobiology and the development of therapeutic strategies for disease management, their translational capacity is limited. There is, therefore, a well-recognised need for innovative in vitro models to reflect chronic lung diseases, which will facilitate mechanism investigation and the advancement of new treatment strategies. In the last decades, lungs have been modelled in healthy and diseased conditions using precision-cut lung slices, organoids, extracellular matrix-derived hydrogels and lung-on-chip systems. These three-dimensional models together provide a wide spectrum of applicability and mimicry of the lung microenvironment. While each system has its own limitations, their advantages over traditional two-dimensional culture systems, or even over animal models, increases the value of in vitro models. Generating new and advanced models with increased translational capacity will not only benefit our understanding of the pathobiology of lung diseases but should also shorten the timelines required for discovery and generation of new therapeutics. This article summarises and provides an outline of the European Respiratory Society research seminar "Innovative 3D models for understanding mechanisms underlying lung diseases: powerful tools for translational research", held in Lisbon, Portugal, in April 2022. Current in vitro models developed for recapitulating healthy and diseased lungs are outlined and discussed with respect to the challenges associated with them, efforts to develop best practices for model generation, characterisation and utilisation of models and state-of-the-art translational potential.
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Affiliation(s)
- Mehmet Nizamoglu
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands
- Both authors contributed equally
| | - Mugdha M Joglekar
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands
- Both authors contributed equally
| | - Catarina R Almeida
- Department of Medical Sciences, Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | | | - Isabelle Dupin
- Centre de Recherche Cardio-thoracique de Bordeaux, Université de Bordeaux, Pessac, France
- INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, Pessac, France
| | - Olivier T Guenat
- Organs-on-Chip Technologies, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Pulmonary Medicine, University Hospital of Bern, Bern, Switzerland
- Department of General Thoracic Surgery, University Hospital of Bern, Bern, Switzerland
| | - Pauline Henrot
- Centre de Recherche Cardio-thoracique de Bordeaux, Université de Bordeaux, Pessac, France
- INSERM, Centre de Recherche Cardio-thoracique de Bordeaux, Pessac, France
- Service d'exploration fonctionnelle respiratoire, CHU de Bordeaux, Pessac, France
| | - Lisette van Os
- Organs-on-Chip Technologies, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Jorge Otero
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Linda Elowsson
- Lung Biology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Ramon Farre
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Janette K Burgess
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands
- University of Groningen, University Medical Center Groningen, W.J. Kolff Institute for Biomedical Engineering and Materials Science-FB41, Groningen, The Netherlands
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Zhang EY, Bartman CM, Prakash YS, Pabelick CM, Vogel ER. Oxygen and mechanical stretch in the developing lung: risk factors for neonatal and pediatric lung disease. Front Med (Lausanne) 2023; 10:1214108. [PMID: 37404808 PMCID: PMC10315587 DOI: 10.3389/fmed.2023.1214108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/01/2023] [Indexed: 07/06/2023] Open
Abstract
Chronic airway diseases, such as wheezing and asthma, remain significant sources of morbidity and mortality in the pediatric population. This is especially true for preterm infants who are impacted both by immature pulmonary development as well as disproportionate exposure to perinatal insults that may increase the risk of developing airway disease. Chronic pediatric airway disease is characterized by alterations in airway structure (remodeling) and function (increased airway hyperresponsiveness), similar to adult asthma. One of the most common perinatal risk factors for development of airway disease is respiratory support in the form of supplemental oxygen, mechanical ventilation, and/or CPAP. While clinical practice currently seeks to minimize oxygen exposure to decrease the risk of bronchopulmonary dysplasia (BPD), there is mounting evidence that lower levels of oxygen may carry risk for development of chronic airway, rather than alveolar disease. In addition, stretch exposure due to mechanical ventilation or CPAP may also play a role in development of chronic airway disease. Here, we summarize the current knowledge of the impact of perinatal oxygen and mechanical respiratory support on the development of chronic pediatric lung disease, with particular focus on pediatric airway disease. We further highlight mechanisms that could be explored as potential targets for novel therapies in the pediatric population.
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Affiliation(s)
- Emily Y. Zhang
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Colleen M. Bartman
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Y. S. Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Christina M. Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Elizabeth R. Vogel
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
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4
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Rezoagli E, Laffey JG, Bellani G. Monitoring Lung Injury Severity and Ventilation Intensity during Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:346-368. [PMID: 35896391 DOI: 10.1055/s-0042-1748917] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure burden by high hospital mortality. No specific pharmacologic treatment is currently available and its ventilatory management is a key strategy to allow reparative and regenerative lung tissue processes. Unfortunately, a poor management of mechanical ventilation can induce ventilation induced lung injury (VILI) caused by physical and biological forces which are at play. Different parameters have been described over the years to assess lung injury severity and facilitate optimization of mechanical ventilation. Indices of lung injury severity include variables related to gas exchange abnormalities, ventilatory setting and respiratory mechanics, ventilation intensity, and the presence of lung hyperinflation versus derecruitment. Recently, specific indexes have been proposed to quantify the stress and the strain released over time using more comprehensive algorithms of calculation such as the mechanical power, and the interaction between driving pressure (DP) and respiratory rate (RR) in the novel DP multiplied by four plus RR [(4 × DP) + RR] index. These new parameters introduce the concept of ventilation intensity as contributing factor of VILI. Ventilation intensity should be taken into account to optimize protective mechanical ventilation strategies, with the aim to reduce intensity to the lowest level required to maintain gas exchange to reduce the potential for VILI. This is further gaining relevance in the current era of phenotyping and enrichment strategies in ARDS.
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Affiliation(s)
- Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland, Galway, Ireland.,Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Saolta University Hospital Group, Galway, Ireland.,Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
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5
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Mechanical stretching of cells and lipid nanoparticles for nucleic acid delivery. J Control Release 2021; 339:208-219. [PMID: 34563590 DOI: 10.1016/j.jconrel.2021.09.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/17/2021] [Indexed: 11/23/2022]
Abstract
Gene therapy has gained popularity in the treatment of incurable diseases. However, cell components, such as surface membrane, cytoskeleton protein, and nuclear envelope, retard the transport of nucleic acids, lowering the transfection efficiency. We developed a physical-chemical hybrid platform (S-RCLs) involving cationic lipid nanoparticles (RCLs) exposed to cyclic stretch. The transfection efficiency and delivery mechanisms of S-RCLs for siRNAs and pDNAs (plasmid DNAs encoding luciferase) were investigated. S-RCLs effectively delivered both siRNAs and pDNAs by overcoming the cell barriers. Mechanistically, S-RCLs promote the cellular uptake mediated by CD44, EH-domain containing 2 (EHD2), and caveolin-1 (CAV-1); intracellular transport via MAP6 Domain Containing 1 (Map6d1) and F-actin; and DNA transcription regulated by LSM3 and Hist1h3e in the nucleus. Thus, S-RCLs are a promising hybrid platform with excellent efficiency and biocompatibility for gene delivery both in vitro and in vivo.
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Atag E, Unal F, Yazan H, Girit S, Uyan ZS, Ergenekon AP, Yayla E, Merttürk E, Telhan L, Meral Ö, Kucuk HB, Gunduz M, Gokdemir Y, Erdem Eralp E, Kiyan G, Cakir E, Ersu R, Karakoc F, Oktem S. Pediatric flexible bronchoscopy in the intensive care unit: A multicenter study. Pediatr Pulmonol 2021; 56:2925-2931. [PMID: 34236776 DOI: 10.1002/ppul.25566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/10/2021] [Accepted: 07/01/2021] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Flexible bronchoscopy (FB) is frequently used for assessment and treatment of patients with respiratory diseases. Our aim was to investigate the contribution of FB to diagnosis and therapy in children admitted to the intensive care units (ICU) and to evaluate the safety of FB in this vulnerable population. METHODS Children less than 18 years of age who underwent FB in the five neonatal and pediatric ICUs in Istanbul between July 1st, 2015 and July 1st, 2020 were included to the study. Demographic and clinical data including bronchoscopy indications, findings, complications, and the contribution of bronchoscopy to the management were retrospectively reviewed. RESULTS One hundred and ninety-six patients were included to the study. The median age was 5 months (range 0.3-205 months). The most common indication of FB was extubation failure (38.3%), followed by suspected airway disease. Bronchoscopic assessments revealed at least one abnormality in 90.8% patients. The most common findings were airway malacia and the presence of excessive airway secretions (47.4% and 35.7%, respectively). Positive contribution of FB was identified in 87.2% of the patients. FB had greater than 1 positive contribution in 138 patients and 80.6% of the patients received a new diagnosis. Medical therapy was modified after the procedure in 39.8% and surgical interventions were pursued in 40% of the patients. Therapeutic lavage was achieved in 18.9%. There were no major complications. CONCLUSION Flexible bronchoscopy is a valuable diagnostic and therapeutic tool in neonatal and pediatric ICUs and is not associated with major complications.
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Affiliation(s)
- Emine Atag
- Division of Pediatric Pulmonology, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Fusun Unal
- Department of Pediatrics, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Hakan Yazan
- Division of Pediatric Pulmonology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey
| | - Saniye Girit
- Division of Pediatric Pulmonology, Faculty of Medicine, Medeniyet University, Istanbul, Turkey
| | - Zeynep Seda Uyan
- Division of Pediatric Pulmonology, Faculty of Medicine, Koc University, Istanbul, Turkey
| | - Almala Pınar Ergenekon
- Division of Pediatric Pulmonology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Esra Yayla
- Department of Pediatrics, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Edanur Merttürk
- Department of Pediatrics, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Leyla Telhan
- Department of Pediatrics, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Özge Meral
- Division of Pediatric Pulmonology, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Hanife Busra Kucuk
- Department of Pediatrics, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey
| | - Mehmet Gunduz
- Division of Neonatalogy, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - Yasemin Gokdemir
- Division of Pediatric Pulmonology, Faculty of Medicine Istanbul, Marmara University, Istanbul, Turkey
| | - Ela Erdem Eralp
- Division of Pediatric Pulmonology, Faculty of Medicine Istanbul, Marmara University, Istanbul, Turkey
| | - Gursu Kiyan
- Department of Pediatric Surgery, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Erkan Cakir
- Division of Pediatric Pulmonology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey
| | - Refika Ersu
- Division of Pediatric Pulmonology, Faculty of Medicine Istanbul, Marmara University, Istanbul, Turkey
| | - Fazilet Karakoc
- Division of Pediatric Pulmonology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Sedat Oktem
- Division of Pediatric Pulmonology, Faculty of Medicine, Medipol University, Istanbul, Turkey
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Yang J, Pan X, Wang L, Yu G. Alveolar cells under mechanical stressed niche: critical contributors to pulmonary fibrosis. Mol Med 2020; 26:95. [PMID: 33054759 PMCID: PMC7556585 DOI: 10.1186/s10020-020-00223-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022] Open
Abstract
Pulmonary fibrosis arises from the repeated epithelial mild injuries and insufficient repair lead to over activation of fibroblasts and excessive deposition of extracellular matrix, which result in a mechanical stretched niche. However, increasing mechanical stress likely exists before the establishment of fibrosis since early micro injuries increase local vascular permeability and prompt cytoskeletal remodeling which alter cellular mechanical forces. It is noteworthy that COVID-19 patients with severe hypoxemia will receive mechanical ventilation as supportive treatment and subsequent pathology studies indicate lung fibrosis pattern. At advanced stages, mechanical stress originates mainly from the stiff matrix since boundaries between stiff and compliant parts of the tissue could generate mechanical stress. Therefore, mechanical stress has a significant role in the whole development process of pulmonary fibrosis. The alveoli are covered by abundant capillaries and function as the main gas exchange unit. Constantly subject to variety of damages, the alveolar epithelium injuries were recently recognized to play a vital role in the onset and development of idiopathic pulmonary fibrosis. In this review, we summarize the literature regarding the effects of mechanical stress on the fundamental cells constituting the alveoli in the process of pulmonary fibrosis, particularly on epithelial cells, capillary endothelial cells, fibroblasts, mast cells, macrophages and stem cells. Finally, we briefly review this issue from a more comprehensive perspective: the metabolic and epigenetic regulation.
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Affiliation(s)
- Juntang Yang
- State Key Laboratory of Cell Differentiation and Regulation, Henan International Joint Laboratory of Pulmonary Fibrosis, Outstanding Overseas Scientists Center for Pulmonary Fibrosis of Henan Province, College of Life Science, Institute of Biomedical Science, Henan Normal University, Xinxiang, Henan, China
| | - Xin Pan
- State Key Laboratory of Cell Differentiation and Regulation, Henan International Joint Laboratory of Pulmonary Fibrosis, Outstanding Overseas Scientists Center for Pulmonary Fibrosis of Henan Province, College of Life Science, Institute of Biomedical Science, Henan Normal University, Xinxiang, Henan, China
| | - Lan Wang
- State Key Laboratory of Cell Differentiation and Regulation, Henan International Joint Laboratory of Pulmonary Fibrosis, Outstanding Overseas Scientists Center for Pulmonary Fibrosis of Henan Province, College of Life Science, Institute of Biomedical Science, Henan Normal University, Xinxiang, Henan, China
| | - Guoying Yu
- State Key Laboratory of Cell Differentiation and Regulation, Henan International Joint Laboratory of Pulmonary Fibrosis, Outstanding Overseas Scientists Center for Pulmonary Fibrosis of Henan Province, College of Life Science, Institute of Biomedical Science, Henan Normal University, Xinxiang, Henan, China.
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8
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Morrell ED, Grazioli S, Hung C, Kajikawa O, Kosamo S, Stapleton RD, Gharib SA, Amado-Rodríguez L, Albaiceta G, Wurfel MM, Matute-Bello G. Alveolar CCN1 is associated with mechanical stretch and acute respiratory distress syndrome severity. Am J Physiol Lung Cell Mol Physiol 2020; 319:L825-L832. [PMID: 32936024 DOI: 10.1152/ajplung.00073.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The cellular communication network factor 1 (CCN1) is a matricellular protein that can modulate multiple tissue responses, including inflammation and repair. We have previously shown that adenoviral overexpression of Ccn1 is sufficient to cause acute lung injury in mice. We hypothesized that CCN1 is present in the airspaces of lungs during the acute phase of lung injury, and higher concentrations are associated with acute respiratory distress syndrome (ARDS) severity. We tested this hypothesis by measuring 1) CCN1 in bronchoalveolar lavage fluid (BALF) and lung homogenates from mice subjected to ventilation-induced lung injury (VILI), 2) Ccn1 gene expression and protein levels in MLE-12 cells (alveolar epithelial cell line) subjected to mechanical stretch, and 3) CCN1 in BALF from mechanically ventilated humans with and without ARDS. BALF CCN1 concentrations and whole lung CCN1 protein levels were significantly increased in mice with VILI (n = 6) versus noninjured controls (n = 6). Ccn1 gene expression and CCN1 protein levels were increased in MLE-12 cells cultured under stretch conditions. Subjects with ARDS (n = 77) had higher BALF CCN1 levels compared with mechanically ventilated subjects without ARDS (n = 45) (P < 0.05). In subjects with ARDS, BALF CCN1 concentrations were associated with higher total protein, sRAGE, and worse [Formula: see text]/[Formula: see text] ratios (all P < 0.05). CCN1 is present in the lungs of mice and humans during the acute inflammatory phase of lung injury, and concentrations are higher in patients with increased markers of severity. Alveolar epithelial cells may be an important source of CCN1 under mechanical stretch conditions.
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Affiliation(s)
- Eric D Morrell
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington.,Veterans Affairs Puget Sound Healthcare System, Seattle, Washington
| | - Serge Grazioli
- Division of Neonatal and Pediatric Intensive Care, Department of Pediatrics, University Hospitals of Geneva, Geneva, Switzerland
| | - Chi Hung
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington
| | - Osamu Kajikawa
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington
| | - Susanna Kosamo
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington
| | | | - Sina A Gharib
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington
| | - Laura Amado-Rodríguez
- Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Cardiac Intensive Care Unit, Hospital Universitario Central de Asturias, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
| | - Guillermo Albaiceta
- Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Cardiac Intensive Care Unit, Hospital Universitario Central de Asturias, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
| | - Mark M Wurfel
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington
| | - Gustavo Matute-Bello
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington.,Veterans Affairs Puget Sound Healthcare System, Seattle, Washington
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Yen S, Preissner M, Bennett E, Dubsky S, Carnibella R, O'Toole R, Roddam L, Jones H, Dargaville PA, Fouras A, Zosky GR. The Link between Regional Tidal Stretch and Lung Injury during Mechanical Ventilation. Am J Respir Cell Mol Biol 2019; 60:569-577. [PMID: 30428271 DOI: 10.1165/rcmb.2018-0143oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The aim of this study was to assess the association between regional tidal volume (Vt), regional functional residual capacity (FRC), and the expression of genes linked with ventilator-induced lung injury. Two groups of BALB/c mice (n = 8 per group) were ventilated for 2 hours using a protective or injurious ventilation strategy, with free-breathing mice used as control animals. Regional Vt and FRC of the ventilated mice was determined by analysis of high-resolution four-dimensional computed tomographic images taken at baseline and after 2 hours of ventilation and corrected for the volume of the region (i.e., specific [s]Vt and specific [s]FRC). RNA concentrations of 21 genes in 10 different lung regions were quantified using a quantitative PCR array. sFRC at baseline varied regionally, independent of ventilation strategy, whereas sVt varied regionally depending on ventilation strategy. The expression of IL-6 (P = 0.04), Ccl2 (P < 0.01), and Ang-2 (P < 0.05) was associated with sVt but not sFRC. The expression of seven other genes varied regionally (IL-1β and RAGE [receptor for advanced glycation end products]) or depended on ventilation strategy (Nfe2l2 [nuclear factor erythroid-derived 2 factor 2], c-fos, and Wnt1) or both (TNF-α and Cxcl2), but it was not associated with regional sFRC or sVt. These observations suggest that regional inflammatory responses to mechanical ventilation are driven primarily by tidal stretch.
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Affiliation(s)
| | - Melissa Preissner
- 2 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria, Australia
| | | | - Stephen Dubsky
- 2 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria, Australia
| | | | | | | | - Heather Jones
- 4 Biomedical Imaging Research Institute.,5 Department of Medicine, and.,6 Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Peter A Dargaville
- 7 Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Graeme R Zosky
- 1 School of Medicine and.,7 Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
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10
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Mechanical ventilation and Streptococcus pneumoniae pneumonia alter mitochondrial homeostasis. Sci Rep 2018; 8:11718. [PMID: 30082877 PMCID: PMC6078986 DOI: 10.1038/s41598-018-30226-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/23/2018] [Indexed: 12/16/2022] Open
Abstract
Required mechanical ventilation (MV) may contribute to bacterial dissemination in patients with Streptococcus pneumoniae pneumonia. Significant variations in plasma mitochondrial DNA (mtDNA) have been reported in sepsis according to the outcome. The impact of lung stretch during MV was addressed in a model of pneumonia. Healthy or S. pneumoniae infected rabbits were submitted to MV or kept spontaneously breathing (SB). Bacterial burden, cytokines release, mitochondrial DNA levels, integrity and transcription were assessed along with 48-hour mortality. Compared with infected SB rabbits, MV rabbits developed more severe pneumonia with greater concentrations of bacteria in the lungs, higher rates of systemic dissemination, higher levels of circulating inflammatory mediators and decreased survival. Pulmonary mtDNA levels were significantly lower in infected animals as compared to non-infected ones, whenever they were SB or MV. After a significant early drop, circulating mtDNA levels returned to baseline values in the infected SB rabbits, but remained low until death in the MV ones. Whole blood ex-vivo stimulation with Streptococcus pneumoniae resulted in a reduction of polymorphonuclear leukocytes mitochondrial density and plasma mtDNA concentrations. Thus, persistent mitochondrial depletion and dysfunction in the infected animals submitted to MV could account for their less efficient immune response against S. pneumoniae.
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11
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Morales Quinteros L, Bringué Roque J, Kaufman D, Artigas Raventós A. Importance of carbon dioxide in the critical patient: Implications at the cellular and clinical levels. Med Intensiva 2018; 43:234-242. [PMID: 29486904 DOI: 10.1016/j.medin.2018.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 01/22/2023]
Abstract
Important recent insights have emerged regarding the cellular and molecular role of carbon dioxide (CO2) and the effects of hypercapnia. The latter may have beneficial effects in patients with acute lung injury, affording reductions in pulmonary inflammation, lessened oxidative alveolar damage, and the regulation of innate immunity and host defenses by inhibiting the expression of inflammatory cytokines. However, other studies suggest that CO2 can have deleterious effects upon the lung, reducing alveolar wound repair in lung injury, decreasing the rate of reabsorption of alveolar fluid, and inhibiting alveolar cell proliferation. Clearly, hypercapnia has both beneficial and harmful consequences, and it is important to determine the net effect under specific conditions. The purpose of this review is to describe the immunological and physiological effects of carbon dioxide, considering their potential consequences in patients with acute respiratory failure.
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Affiliation(s)
| | | | - David Kaufman
- Division of Pulmonary, Critical Care & Sleep, NYU School of Medicine, New York, NY, Estados Unidos
| | - Antonio Artigas Raventós
- Servicio de Medicina Intensiva, Hospital Universitario Sagrat Cor, Barcelona, España; Universidad Autónoma de Barcelona, Sabadell, Barcelona, España; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, España
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Suryadevara V, Fu P, Ebenezer DL, Berdyshev E, Bronova IA, Huang LS, Harijith A, Natarajan V. Sphingolipids in Ventilator Induced Lung Injury: Role of Sphingosine-1-Phosphate Lyase. Int J Mol Sci 2018; 19:E114. [PMID: 29301259 PMCID: PMC5796063 DOI: 10.3390/ijms19010114] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 12/14/2022] Open
Abstract
Mechanical ventilation (MV) performed in respiratory failure patients to maintain lung function leads to ventilator-induced lung injury (VILI). This study investigates the role of sphingolipids and sphingolipid metabolizing enzymes in VILI using a rodent model of VILI and alveolar epithelial cells subjected to cyclic stretch (CS). MV (0 PEEP (Positive End Expiratory Pressure), 30 mL/kg, 4 h) in mice enhanced sphingosine-1-phosphate lyase (S1PL) expression, and ceramide levels, and decreased S1P levels in lung tissue, thereby leading to lung inflammation, injury and apoptosis. Accumulation of S1P in cells is a balance between its synthesis catalyzed by sphingosine kinase (SphK) 1 and 2 and catabolism mediated by S1P phosphatases and S1PL. Thus, the role of S1PL and SphK1 in VILI was investigated using Sgpl1+/- and Sphk1-/- mice. Partial genetic deletion of Sgpl1 protected mice against VILI, whereas deletion of SphK1 accentuated VILI in mice. Alveolar epithelial MLE-12 cells subjected to pathophysiological 18% cyclic stretch (CS) exhibited increased S1PL protein expression and dysregulation of sphingoid bases levels as compared to physiological 5% CS. Pre-treatment of MLE-12 cells with S1PL inhibitor, 4-deoxypyridoxine, attenuated 18% CS-induced barrier dysfunction, minimized cell apoptosis and cytokine secretion. These results suggest that inhibition of S1PL that increases S1P levels may offer protection against VILI.
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Affiliation(s)
- Vidyani Suryadevara
- Department of Bioengineering, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA.
| | - Panfeng Fu
- Department of Pharmacology, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
| | - David Lenin Ebenezer
- Department of Pharmacology, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
| | - Evgeny Berdyshev
- Department of Pharmacology, Department of Medicine, National Jewish Health Center, Denver, CO 80206, USA.
| | - Irina A Bronova
- Department of Pharmacology, Department of Medicine, National Jewish Health Center, Denver, CO 80206, USA.
| | - Long Shuang Huang
- Department of Pharmacology, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
| | - Anantha Harijith
- Department of Pediatrics, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
| | - Viswanathan Natarajan
- Department of Pharmacology, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
- Department of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA.
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Le Guen M, Grassin-Delyle S, Naline E, Buenestado A, Brollo M, Longchampt E, Kleinmann P, Devillier P, Faisy C. The impact of low-frequency, low-force cyclic stretching of human bronchi on airway responsiveness. Respir Res 2016; 17:151. [PMID: 27842540 PMCID: PMC5109770 DOI: 10.1186/s12931-016-0464-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 11/01/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In vivo, the airways are constantly subjected to oscillatory strain (due to tidal breathing during spontaneous respiration) and (in the event of mechanical ventilation) positive pressure. This exposure is especially problematic for the cartilage-free bronchial tree. The effects of cyclic stretching (other than high-force stretching) have not been extensively characterized. Hence, the objective of the present study was to investigate the functional and transcriptional response of human bronchi to repetitive mechanical stress caused by low-frequency, low-force cyclic stretching. METHODS After preparation and equilibration in an organ bath, human bronchial rings from 66 thoracic surgery patients were stretched in 1-min cycles of elongation and relaxation over a 60-min period. For each segment, the maximal tension corresponded to 80% of the reference contraction (the response to 3 mM acetylcholine). The impact of cyclic stretching (relative to non-stretched controls) was examined by performing functional assessments (epithelium removal and incubation with sodium channel agonists/antagonists or inhibitors of intracellular pathways), biochemical assays of the organ bath fluid (for detecting the release of pro-inflammatory cytokines), and RT-PCR assays of RNA isolated from tissue samples. RESULTS The application of low-force cyclic stretching to human bronchial rings for 60 min resulted in an immediate, significant increase in bronchial basal tone, relative to non-cyclic stretching (4.24 ± 0.16 g vs. 3.28 ± 0.12 g, respectively; p < 0.001). This cyclic stimulus also increased the affinity for acetylcholine (-log EC50: 5.67 ± 0.07 vs. 5.32 ± 0.07, respectively; p p < 0.001). Removal of airway epithelium and pretreatment with the Rho-kinase inhibitor Y27632 and inward-rectifier K+ or L-type Ca2+ channel inhibitors significantly modified the basal tone response. Exposure to L-NAME had opposing effects in all cases. Pro-inflammatory pathways were not involved in the response; cyclic stretching up-regulated the early mRNA expression of MMP9 only, and was not associated with changes in organ bath levels of pro-inflammatory mediators. CONCLUSION Low-frequency, low-force cyclic stretching of whole human bronchi induced a myogenic response rather than activation of the pro-inflammatory signaling pathways mediated by mechanotransduction.
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Affiliation(s)
- Morgan Le Guen
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France. .,Department of Anesthesiology, Hôpital Foch, Université Versailles - Saint-Quentin, Suresnes, France.
| | - Stanislas Grassin-Delyle
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Emmanuel Naline
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Amparo Buenestado
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Marion Brollo
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | | | - Philippe Kleinmann
- Department of Thoracic Surgery, Centre Médico-Chirurgical du Val d'Or, Saint-Cloud, France
| | - Philippe Devillier
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Christophe Faisy
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
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Tian Y, Gawlak G, O'Donnell JJ, Mambetsariev I, Birukova AA. Modulation of Endothelial Inflammation by Low and High Magnitude Cyclic Stretch. PLoS One 2016; 11:e0153387. [PMID: 27128976 PMCID: PMC4851399 DOI: 10.1371/journal.pone.0153387] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 03/29/2016] [Indexed: 11/29/2022] Open
Abstract
Excessive mechanical ventilation exerts pathologic mechanical strain on lung vascular endothelium and promotes endothelial cell (EC) inflammatory activation; however, the specific mechanisms underlying EC inflammatory response caused by mechanical ventilation related cyclic stretch (CS) remain unclear. This study investigated the effects of chronic exposure to CS at physiologic (5%) and pathologic (18%) magnitude on pulmonary EC inflammatory status in control conditions and bacterial lipopolysacharide (LPS)-stimulated conditions. EC exposure to high or low CS magnitudes for 28–72 hrs had distinct effects on EC inflammatory activation. 18% CS increased surface expression of endothelial adhesion molecule ICAM1 and release of its soluble form (sICAM1) and inflammatory cytokine IL-8 by CS-stimulated pulmonary endothelial cells (EC). EC inflammatory activation was not observed in EC exposed to 5% CS. Chronic exposure to 18% CS, but not to 5% CS, augmented ICAM1 and IL-8 production and EC monolayer barrier disruption induced by LPS. 18% CS, but not 5% CS, stimulated expression of RhoA GTPase-specific guanine nucleotide exchange factor GEF-H1. GEF-H1 knockdown using gene-specific siRNA abolished 18% CS-induced ICAM1 expression and sICAM1 and IL-8 release by EC. GEF-H1 knockdown also prevented disruption of EC monolayer integrity and attenuated sICAM1 and IL-8 release in the two-hit model of EC barrier dysfunction caused by combined stimulation with 18% CS and LPS. These data demonstrate that exacerbation of inflammatory response by pulmonary endothelium exposed to excessive mechanical stretch is mediated by CS-induced induction of Rho activating protein GEF-H1.
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Affiliation(s)
- Yufeng Tian
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, United States of America
| | - Grzegorz Gawlak
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, United States of America
| | - James J. O'Donnell
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, United States of America
| | - Isa Mambetsariev
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, United States of America
| | - Anna A. Birukova
- Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, United States of America
- * E-mail:
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Rizzo AN, Sammani S, Esquinca AE, Jacobson JR, Garcia JGN, Letsiou E, Dudek SM. Imatinib attenuates inflammation and vascular leak in a clinically relevant two-hit model of acute lung injury. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1294-304. [PMID: 26432864 DOI: 10.1152/ajplung.00031.2015] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 09/27/2015] [Indexed: 12/29/2022] Open
Abstract
Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), an illness characterized by life-threatening vascular leak, is a significant cause of morbidity and mortality in critically ill patients. Recent preclinical studies and clinical observations have suggested a potential role for the chemotherapeutic agent imatinib in restoring vascular integrity. Our prior work demonstrates differential effects of imatinib in mouse models of ALI, namely attenuation of LPS-induced lung injury but exacerbation of ventilator-induced lung injury (VILI). Because of the critical role of mechanical ventilation in the care of patients with ARDS, in the present study we pursued an assessment of the effectiveness of imatinib in a "two-hit" model of ALI caused by combined LPS and VILI. Imatinib significantly decreased bronchoalveolar lavage protein, total cells, neutrophils, and TNF-α levels in mice exposed to LPS plus VILI, indicating that it attenuates ALI in this clinically relevant model. In subsequent experiments focusing on its protective role in LPS-induced lung injury, imatinib attenuated ALI when given 4 h after LPS, suggesting potential therapeutic effectiveness when given after the onset of injury. Mechanistic studies in mouse lung tissue and human lung endothelial cells revealed that imatinib inhibits LPS-induced NF-κB expression and activation. Overall, these results further characterize the therapeutic potential of imatinib against inflammatory vascular leak.
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Affiliation(s)
- Alicia N Rizzo
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois; University of Illinois at Chicago, Department of Pharmacology, Chicago, Illinois
| | - Saad Sammani
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois
| | - Adilene E Esquinca
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois
| | - Jeffrey R Jacobson
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois
| | - Joe G N Garcia
- Arizona Health Sciences Center, University of Arizona, Tucson, Arizona
| | - Eleftheria Letsiou
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois
| | - Steven M Dudek
- University of Illinois Hospital and Health Sciences System, Division of Pulmonary, Critical Care, Sleep and Allergy, Chicago, Illinois; University of Illinois at Chicago, Department of Pharmacology, Chicago, Illinois;
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16
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Mathematical model of a heterogeneous pulmonary acinus structure. Comput Biol Med 2015; 62:25-32. [PMID: 25912985 DOI: 10.1016/j.compbiomed.2015.03.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/02/2015] [Accepted: 03/31/2015] [Indexed: 01/06/2023]
Abstract
The pulmonary acinus is a gas exchange unit distal to the terminal bronchioles. A model of its structure is important for the computational investigation of mechanical phenomena at the acinus level. We propose a mathematical model of a heterogeneous acinus structure composed of alveoli of irregular sizes, shapes, and locations. The alveoli coalesce into an intricately branched ductal tree, which meets the space-filling requirement of the acinus structure. Our model uses Voronoi tessellation to generate an assemblage of the alveolar or ductal airspace, and Delaunay tessellation and simulated annealing for the ductal tree structure. The modeling condition is based on average acinar and alveolar volume characteristics from published experimental information. By applying this modeling technique to the acinus of healthy mature rats, we demonstrate that the proposed acinus structure model reproduces the available experimental information. In the model, the shape and size of alveoli and the length, generation, tortuosity, and branching angle of the ductal paths are distributed in several ranges. This approach provides a platform for investigating the heterogeneous nature of the acinus structure and its relationship with mechanical phenomena at the acinus level.
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17
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High-frequency percussive ventilation and initial biomarker levels of lung injury in patients with minor burns after smoke inhalation injury. Burns 2015; 41:65-70. [DOI: 10.1016/j.burns.2014.05.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 05/06/2014] [Accepted: 05/09/2014] [Indexed: 11/23/2022]
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Gamerdinger K, Wernet F, Smudde E, Schneider M, Guttmann J, Schumann S. Mechanical load and mechanical integrity of lung cells - experimental mechanostimulation of epithelial cell- and fibroblast-monolayers. J Mech Behav Biomed Mater 2014; 40:201-209. [PMID: 25241284 DOI: 10.1016/j.jmbbm.2014.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 08/10/2014] [Accepted: 08/11/2014] [Indexed: 11/26/2022]
Abstract
Experimental mechanostimulation of soft biologic tissue is widely used to investigate cellular responses to mechanical stress or strain. Reactions on mechanostimulation are investigated in terms of morphological changes, inflammatory responses and apoptosis/necrosis induction on a cellular level. In this context, the analysis of the mechanical characteristics of cell-layers might allow to indicate patho-physiological changes in the cell-cell contacts. Recently, we described a device for experimental mechanostimulation that allows simultaneous measurement of the mechanical characteristics of cell-monolayers. Here, we investigated how cultivated lung epithelial cell- and fibroblast-monolayers behave mechanically under different amplitudes of biaxial distension. The cell monolayers were sinusoidally deflected to 5%, 10% or 20% surface gain and their mechanical properties during mechanostimulation were analyzed. With increasing stimulation amplitudes more pronounced reductions of cell junctions were observed. These findings were accompanied by a substantial loss of monolayer rigidity. Pulmonary fibroblast monolayers were initially stiffer but were stronger effected by the mechanostimulation compared to epithelial cell-monolayers. We conclude that, according to their biomechanical function within the pulmonary tissue, epithelial cells and fibroblasts differ with respect to their mechanical characteristics and tolerance of mechanical load.
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Affiliation(s)
- Katharina Gamerdinger
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany.
| | - Florian Wernet
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany
| | - Eva Smudde
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany
| | - Matthias Schneider
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany
| | - Josef Guttmann
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany
| | - Stefan Schumann
- Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Hugstetter Straße 55, D-79106 Freiburg, Germany
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Ruberto F, Bergantino B, Testa MC, D'Arena C, Zullino V, Congi P, Paglialunga SG, Diso D, Venuta F, Pugliese F. Low-flow venovenous CO₂ removal in association with lung protective ventilation strategy in patients who develop severe progressive respiratory acidosis after lung transplantation. Transplant Proc 2014; 45:2741-5. [PMID: 24034037 DOI: 10.1016/j.transproceed.2013.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Primary graft dysfunction (PGD) might occur after lung transplantation. In some severe cases, conventional therapies like ventilatory support, administration of inhaled nitric oxide (iNO), and intravenous prostacyclins are not sufficient to provide an adequate gas exchange. The aim of our study was to evaluate the use of a lung protective ventilation strategy associated with a low-flow venovenous CO2 removal treatment to reduce ventilator-associated injury in patients that develop severe PGD after lung transplantation. METHODS From January 2009 to January 2011, 3 patients developed PGD within 24 hours after lung transplantation. In addition to conventional medical treatment, including hemodynamic support, iNO and prostaglandin E1 (PGE1), we initiated a ventilatory protective strategy associated with low-flow venovenous CO2 removal treatment (LFVVECCO2R). Hemodynamic and respiratory parameters were assessed at baseline as well as after 3, 12, 24, and 48 hours. RESULTS No adverse events were registered. Despite decreased baseline elevated pulmonary positive pressures, application of a protective ventilation strategy with LFVVECCO2R reduced PaCO2 and pulmonary infiltrates as well as increased pH values and PaO2/FiO2 ratios. Every patient showed simultaneous improvement of clinical and hemodynamic conditions. They were weaned from mechanical ventilation and extubated after 24 hours after the use of the low-flow venovenous CO2 removal device. CONCLUSION The use of LFVVECCO2R together with a protective lung ventilation strategy during the perioperative period of lung transplantation may be a valid clinical strategy for patients with PGD and severe respiratory acidosis occured despite adequate mechanical ventilation.
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Affiliation(s)
- F Ruberto
- Dipartimento di Scienze Anestesiologiche, Medicina Critica e Terapia del Dolore, "Sapienza" University of Rome, Policilinico Umberto I, Rome, Italy.
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Protective Ventilatory Approaches to One-Lung Ventilation: More than Reduction of Tidal Volume. CURRENT ANESTHESIOLOGY REPORTS 2014. [DOI: 10.1007/s40140-014-0057-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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[Ventilator-induced immune dysfunction]. MEDECINE INTENSIVE REANIMATION 2014; 23:9-16. [PMID: 32288738 PMCID: PMC7117828 DOI: 10.1007/s13546-014-0846-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/26/2013] [Indexed: 10/30/2022]
Abstract
Although mechanical ventilation is an essential support in patients admitted to the intensive care unit, clinical and experimental studies have shown that it could be harmful and could induce lung injury. Pulmonary and immune cells can convert mechanical stimuli into biological signals that will lead to inflammation. This sterile inflammation both locally and systemically will cause immunosuppression.
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Peñuelas O, Melo E, Sánchez C, Sánchez I, Quinn K, Ferruelo A, Pérez-Vizcaíno F, Esteban A, Navajas D, Nin N, Lorente JA, Farré R. Antioxidant effect of human adult adipose-derived stromal stem cells in alveolar epithelial cells undergoing stretch. Respir Physiol Neurobiol 2013; 188:1-8. [PMID: 23643709 DOI: 10.1016/j.resp.2013.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 04/07/2013] [Accepted: 04/08/2013] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Alveolar epithelial cells undergo stretching during mechanical ventilation. Stretch can modify the oxidative balance in the alveolar epithelium. The aim of the present study was to evaluate the antioxidant role of human adult adipose tissue-derived stromal cells (hADSCs) when human alveolar epithelial cells were subjected to injurious cyclic overstretching. METHODS A549 cells were subjected to biaxial stretch (0-15% change in surface area for 24h, 0.2Hz) with and without hADSCs. At the end of the experiments, oxidative stress was measured as superoxide generation using positive nuclear dihydroethidium (DHE) staining, superoxide dismutase (SOD) activity in cell lysates, 8-isoprostane concentrations in supernatant, and 3-nitrotyrosine by indirect immunofluorescence in fixed cells. RESULTS Cyclically stretching of AECs induced a significant decrease in SOD activity, and an increase in 8-isoprostane concentrations, DHE staining and 3-nitrotyrosine staining compared with non-stretched cells. Treatment with hADSCs significantly attenuated stretch-induced changes in SOD activity, 8-isoprostane concentrations, DHE and 3-nitrotyrosine staining. CONCLUSION These data suggest that hADSCs have an anti-oxidative effect in human alveolar epithelial cells undergoing cyclic stretch.
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Affiliation(s)
- Oscar Peñuelas
- Critical Care Department, Hospital Universitario de Getafe, Madrid, Spain.
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Abstract
PURPOSE OF REVIEW Mechanical ventilation is essential for the support of critically ill patients, but may aggravate lung damage, leading to ventilator-associated lung injury (VALI). VALI results from a succession of events beginning with mechanical alteration of lung parenchyma, because of disproportionate stress and strain. The resulting structural tension initiates a biological inflammatory cascade; however, tension can reach the limits of stress, triggering the destruction of structures. This article reviews and discusses the ongoing research into the mechanisms of VALI and their implications for the management of ventilated patients. RECENT FINDINGS Several experimental and clinical studies have been performed to evaluate the contribution of pathogenic mechanical forces to organ and cellular deformation and the implications for guiding ventilator management in patients at risk for VALI. VALI may be attenuated by reducing tidal volume, but the key variable in determining pulmonary overdistension is transpulmonary pressure. Other parameters associated with the induction of VALI include positive end-expiratory pressure, inspiratory airflow and time, and respiratory frequency. SUMMARY How ventilation strategy, specific mechanisms of mechanotransduction, and their individual threshold values impact on VALI remains to be elucidated. In addition, clinical studies are required to evaluate the usefulness of individualized ventilator strategies based on lung mechanics.
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The role of purinergic signaling on deformation induced injury and repair responses of alveolar epithelial cells. PLoS One 2011; 6:e27469. [PMID: 22087324 PMCID: PMC3210789 DOI: 10.1371/journal.pone.0027469] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 10/17/2011] [Indexed: 01/11/2023] Open
Abstract
Cell wounding is an important driver of the innate immune response of ventilator-injured lungs. We had previously shown that the majority of wounded alveolus resident cells repair and survive deformation induced insults. This is important insofar as wounded and repaired cells may contribute to injurious deformation responses commonly referred to as biotrauma. The central hypothesis of this communication states that extracellular adenosine-5′ triphosphate (ATP) promotes the repair of wounded alveolus resident cells by a P2Y2-Receptor dependent mechanism. Using primary type 1 alveolar epithelial rat cell models subjected to micropuncture injury and/or deforming stress we show that 1) stretch causes a dose dependent increase in cell injury and ATP media concentrations; 2) enzymatic depletion of extracellular ATP reduces the probability of stretch induced wound repair; 3) enriching extracellular ATP concentrations facilitates wound repair; 4) purinergic effects on cell repair are mediated by ATP and not by one of its metabolites; and 5) ATP mediated cell salvage depends at least in part on P2Y2-R activation. While rescuing cells from wounding induced death may seem appealing, it is possible that survivors of membrane wounding become governors of a sustained pro-inflammatory state and thereby perpetuate and worsen organ function in the early stages of lung injury syndromes. Means to uncouple P2Y2-R mediated cytoprotection from P2Y2-R mediated inflammation and to test the preclinical efficacy of such an undertaking deserve to be explored.
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Manejo de la falla respiratoria catastrófica en el adulto. REVISTA MÉDICA CLÍNICA LAS CONDES 2011. [DOI: 10.1016/s0716-8640(11)70427-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
Since its introduction into the management of the acute respiratory distress syndrome, mechanical ventilation has been so strongly interwoven with its side effects that it came to be considered as invariably dangerous. Over the decades, attention has shifted from gross barotrauma to volutrauma and, more recently, to atelectrauma and biotrauma. In this article, we describe the anatomical and physiologic framework in which ventilator-induced lung injury may occur. We address the concept of lung stress/strain as applied to the whole lung or specific pulmonary regions. We challenge some common beliefs, such as separately studying the dangerous effects of different tidal volumes (end inspiration) and end-expiratory positive pressures. Based on available data, we suggest that stress at rupture is only rarely reached and that high tidal volume induces ventilator-induced lung injury by augmenting the pressure heterogeneity at the interface between open and constantly closed units. We believe that ventilator-induced lung injury occurs only when a given threshold is exceeded; below this limit, mechanical ventilation is likely to be safe.
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Angiopoietin-1 treatment reduces inflammation but does not prevent ventilator-induced lung injury. PLoS One 2010; 5:e15653. [PMID: 21179479 PMCID: PMC3001877 DOI: 10.1371/journal.pone.0015653] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 11/14/2010] [Indexed: 01/28/2023] Open
Abstract
Background Loss of integrity of the epithelial and endothelial barriers is thought to be a prominent feature of ventilator-induced lung injury (VILI). Based on its function in vascular integrity, we hypothesize that the angiopoietin (Ang)-Tie2 system plays a role in the development of VILI. The present study was designed to examine the effects of mechanical ventilation on the Ang-Tie2 system in lung tissue. Moreover, we evaluated whether treatment with Ang-1, a Tie2 receptor agonist, protects against inflammation, vascular leakage and impaired gas exchange induced by mechanical ventilation. Methods Mice were anesthetized, tracheotomized and mechanically ventilated for 5 hours with either an inspiratory pressure of 10 cmH2O (‘low’ tidal volume ∼7.5 ml/kg; LVT) or 18 cmH2O (‘high’ tidal volume ∼15 ml/kg; HVT). At initiation of HVT-ventilation, recombinant human Ang-1 was intravenously administered (1 or 4 µg per animal). Non-ventilated mice served as controls. Results HVT-ventilation influenced the Ang-Tie2 system in lungs of healthy mice since Ang-1, Ang-2 and Tie2 mRNA were decreased. Treatment with Ang-1 increased Akt-phosphorylation indicating Tie2 signaling. Ang-1 treatment reduced infiltration of granulocytes and expression of keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP)-2, monocyte chemotactic protein (MCP)-1 and interleukin (IL)-1β caused by HVT-ventilation. Importantly, Ang-1 treatment did not prevent vascular leakage and impaired gas exchange in HVT-ventilated mice despite inhibition of inflammation, vascular endothelial growth factor (VEGF) and Ang-2 expression. Conclusions Ang-1 treatment downregulates pulmonary inflammation, VEGF and Ang-2 expression but does not protect against vascular leakage and impaired gas exchange induced by HVT-ventilation.
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Taniguchi LU, Caldini EG, Velasco IT, Negri EM. Cytoskeleton and mechanotransduction in the pathophysiology of ventilator-induced lung injury. J Bras Pneumol 2010; 36:363-71. [PMID: 20625675 DOI: 10.1590/s1806-37132010000300015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 01/26/2010] [Indexed: 01/27/2023] Open
Abstract
Although mechanical ventilation is an important therapy, it can result in complications. One major complication is ventilator-induced lung injury, which is caused by alveolar hyperdistension, leading to an inflammatory process, with neutrophilic infiltration, hyaline membrane formation, fibrogenesis and impaired gas exchange. In this process, cellular mechanotransduction of the overstretching stimulus is mediated by means of the cytoskeleton and its cell-cell and cell-extracellular matrix interactions, in such a way that the mechanical stimulus of ventilation is translated into an intracellular biochemical signal, inducing endothelial activation, pulmonary vascular permeability, leukocyte chemotaxis, cytokine production and, possibly, distal organ failure. Clinical studies have shown the relationship between pulmonary distension and mortality in patients with ventilator-induced lung injury. However, although the cytoskeleton plays a fundamental role in the pathogenesis of ventilator-induced lung injury, there have been few in vivo studies of alterations in the cytoskeleton and in cytoskeleton-associated proteins during this pathological process.
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Affiliation(s)
- Leandro Utino Taniguchi
- Faculdade de Medicina da Universidade de São Paulo, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil.
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Plataki M, Hubmayr RD. The physical basis of ventilator-induced lung injury. Expert Rev Respir Med 2010. [PMID: 20524920 DOI: 10.1586/ers.10.28.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although mechanical ventilation (MV) is a life-saving intervention for patients with acute respiratory distress syndrome (ARDS), it can aggravate or cause lung injury, known as ventilator-induced lung injury (VILI). The biophysical characteristics of heterogeneously injured ARDS lungs increase the parenchymal stress associated with breathing, which is further aggravated by MV. Cells, in particular those lining the capillaries, airways and alveoli, transform this strain into chemical signals (mechanotransduction). The interaction of reparative and injurious mechanotransductive pathways leads to VILI. Several attempts have been made to identify clinical surrogate measures of lung stress/strain (e.g., density changes in chest computed tomography, lower and upper inflection points of the pressure-volume curve, plateau pressure and inflammatory cytokine levels) that could be used to titrate MV. However, uncertainty about the topographical distribution of stress relative to that of the susceptibility of the cells and tissues to injury makes the existence of a single 'global' stress/strain injury threshold doubtful.
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Affiliation(s)
- Maria Plataki
- Thoracic Disease Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Abstract
Although mechanical ventilation (MV) is a life-saving intervention for patients with acute respiratory distress syndrome (ARDS), it can aggravate or cause lung injury, known as ventilator-induced lung injury (VILI). The biophysical characteristics of heterogeneously injured ARDS lungs increase the parenchymal stress associated with breathing, which is further aggravated by MV. Cells, in particular those lining the capillaries, airways and alveoli, transform this strain into chemical signals (mechanotransduction). The interaction of reparative and injurious mechanotransductive pathways leads to VILI. Several attempts have been made to identify clinical surrogate measures of lung stress/strain (e.g., density changes in chest computed tomography, lower and upper inflection points of the pressure-volume curve, plateau pressure and inflammatory cytokine levels) that could be used to titrate MV. However, uncertainty about the topographical distribution of stress relative to that of the susceptibility of the cells and tissues to injury makes the existence of a single 'global' stress/strain injury threshold doubtful.
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Affiliation(s)
- Maria Plataki
- Thoracic Disease Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Rolf D Hubmayr
- Thoracic Disease Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Charles PE, Barbar SD. Toll-like receptors: a link between mechanical ventilation, innate immunity and lung injury? Intensive Care Med 2010; 36:909-11. [PMID: 20397010 DOI: 10.1007/s00134-010-1804-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 02/12/2010] [Indexed: 10/19/2022]
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Hong CM, Xu DZ, Lu Q, Cheng Y, Pisarenko V, Doucet D, Brown M, Aisner S, Zhang C, Deitch EA, Delphin E. Low tidal volume and high positive end-expiratory pressure mechanical ventilation results in increased inflammation and ventilator-associated lung injury in normal lungs. Anesth Analg 2010; 110:1652-60. [PMID: 20103541 DOI: 10.1213/ane.0b013e3181cfc416] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Protective mechanical ventilation with low tidal volume (Vt) and low plateau pressure reduces mortality and decreases the length of mechanical ventilation in patients with acute respiratory distress syndrome. Mechanical ventilation that will protect normal lungs during major surgical procedures of long duration may improve postoperative outcomes. We performed an animal study comparing 3 ventilation strategies used in the operating room in normal lungs. We compared the effects on pulmonary mechanics, inflammatory mediators, and lung tissue injury. METHODS Female pigs were randomized into 3 groups. Group H-Vt/3 (n = 6) was ventilated with a Vt of 15 mL/kg predicted body weight (PBW)/positive end-expiratory pressure (PEEP) of 3 cm H(2)O, group L-Vt/3 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 3 cm H(2)O, and group L-Vt/10 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 10 cm H(2)O, for 8 hours. Hemodynamics, airway mechanics, arterial blood gases, and inflammatory markers were monitored. Bronchoalveolar lavage (BAL) was analyzed for inflammatory markers and protein concentration. The right lower lobe was assayed for mRNA of specific cytokines. The right lower lobe and right upper lobe were evaluated histologically. RESULTS In contrast to groups H-Vt/3 and L-Vt/3, group L-Vt/10 exhibited a 6-fold increase in inflammatory mediators in BAL (P < 0.001). Cytokines in BAL were similar in groups H-Vt/3 and L-Vt/3. Group H-Vt/3 had a significantly lower lung injury score than groups L-Vt/3 and L-Vt/10. CONCLUSION Comparing intraoperative strategies, ventilation with high PEEP resulted in increased production of inflammatory markers. Low PEEP resulted in lower levels of inflammatory markers. High Vt/low PEEP resulted in less histologic lung injury.
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Affiliation(s)
- Caron M Hong
- Department of Anesthesiology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA
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Chan MWC, Hinz B, McCulloch CA. Mechanical induction of gene expression in connective tissue cells. Methods Cell Biol 2010; 98:178-205. [PMID: 20816235 DOI: 10.1016/s0091-679x(10)98008-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The extracellular matrices of mammals undergo coordinated synthesis and degradation, dynamic remodeling processes that enable tissue adaptations to a broad range of environmental factors, including applied mechanical forces. The soft and mineralized connective tissues of mammals also exhibit a wide repertoire of mechanical properties, which enable their tissue-specific functions and modulate cellular responses to forces. The expression of genes in response to applied forces are important for maintaining the support, attachment, and function of various organs including kidney, heart, liver, lung, joint, and periodontium. Several high-prevalence diseases of extracellular matrices including arthritis, heart failure, and periodontal diseases involve pathological levels of mechanical forces that impact the gene expression repertoires and function of bone, cartilage, and soft connective tissues. Recent work on the application of mechanical forces to cultured connective tissue cells and various in vivo force models have enabled study of the regulatory networks that control mechanically induced gene expression in connective tissue cells. In addition to the influence of mechanical forces on the expression of type 1 collagen, which is the most abundant protein of mammals, new work has shown that the expression of a wide range of matrix, signaling, and cytoskeletal proteins are regulated by exogenous mechanical forces and by the forces generated by cells themselves. In this chapter, we first discuss the fundamental nature of the extracellular matrix in health and the impact of mechanical forces. Next we consider the utilization of several, widely employed model systems for mechanical stimulation of cells. Finally, we consider in detail how application of tensile forces to cultured cardiac fibroblasts can be used for the characterization of the signaling systems by which mechanical forces regulate myofibroblast differentiation that is seen in cardiac pressure overload.
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Affiliation(s)
- Matthew W C Chan
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Fitzgerald Building, Toronto, ON, Canada M5S 3E2
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Early physiological and biological features in three animal models of induced acute lung injury. Intensive Care Med 2009; 36:347-55. [PMID: 19841895 DOI: 10.1007/s00134-009-1695-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 10/02/2009] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Critically ill patients often develop acute lung injury (ALI) in the context of different clinical conditions. We aimed to explore differences in early local and systemic features in three experimental animal models of ALI. METHODS Mechanically ventilated male Sprague-Dawley rats were randomized to high tidal volume (VT) ventilation (HVT) (n = 8, VT 24 ml/kg), massive brain injury (MBI) (n = 8, VT 8 ml/kg) or endotoxemia (LPS) (n = 8, VT 8 ml/kg). Each experimental group had its own control group of eight rats (VT 8 ml/kg). We measured arterial blood gases, mean arterial pressure, lung compliance, inflammatory mediators in plasma and their expression and gelatinase activity in the lungs after 3 h of injury. RESULTS Despite maintaining relatively normal lung function without evidence of important structural changes, we observed altered lung and systemic inflammatory responses in all three experimental models. LPS triggered the most robust inflammatory response and HVT the lowest systemic proinflammatory response. The HVT group had higher Il6, Tnf and Cxcl2 mRNA in lungs than MBI animals. Metalloproteinase activity/expression and neutrophilic recruitment in the lungs were higher in HVT than in LPS or MBI. CONCLUSIONS The early responses to direct or remote lung insult in our three models of ALI captured different physiological and biological features that could lead to respiratory and/or multiorgan failure.
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Pulmonary atelectasis during low stretch ventilation: "open lung" versus "lung rest" strategy. Crit Care Med 2009; 37:1046-53. [PMID: 19237916 DOI: 10.1097/ccm.0b013e3181968e7e] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Limiting tidal volume (VT) may minimize ventilator-induced lung injury (VILI). However, atelectasis induced by low VT ventilation may cause ultrastructural evidence of cell disruption. Apoptosis seems to be involved as protective mechanisms from VILI through the involvement of mitogen-activated protein kinases (MAPKs). We examined the hypothesis that atelectasis may influence the response to protective ventilation through MAPKs. DESIGN Prospective randomized study. SETTING University animal laboratory. SUBJECTS Adult male 129/Sv mice. INTERVENTIONS Isolated, nonperfused lungs were randomized to VILI: VT of 20 mL/kg and positive end-expiratory pressure (PEEP) zero; low stretch/lung rest: VT of 6 mL/kg and 8-10 cm H2O of PEEP; low stretch/open lung: VT of 6 mL/kg, two recruitment maneuvers and 14-16 cm H2O of PEEP. Ventilator settings were adjusted using the stress index. MEASUREMENT AND MAIN RESULT Both low stretch strategies equally blunted the VILI-induced derangement of respiratory mechanics (static volume-pressure curve), lung histology (hematoxylin and eosin), and inflammatory mediators (interleukin-6, macrophage inflammatory protein-2 [enzyme-linked immunosorbent assay], and inhibitor of nuclear factor-kB[Western blot]). VILI caused nuclear swelling and membrane disruption of pulmonary cells (electron microscopy). Few pulmonary cells with chromatin condensation and fragmentation were seen during both low stretch strategies. However, although cell thickness during low stretch/open lung was uniform, low stretch/lung rest demonstrated thickening of epithelial cells and plasma membrane bleb formation. Compared with the low stretch/open lung, low stretch/lung rest caused a significant decrease in apoptotic cells (terminal deoxynucleotidyl transferase mediated deoxyuridine-triphosphatase nick end-labeling) and tissue expression of caspase-3 (Western blot). Both low stretch strategies attenuated the activation of MAPKs. Such reduction was larger during low stretch/open lung than during low stretch/lung rest (p < 0.001). CONCLUSION Low stretch strategies provide similar attenuation of VILI. However, low stretch/lung rest strategy is associated to less apoptosis and more ultrastructural evidence of cell damage possibly through MAPKs-mediated pathway.
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Matsuyama H, Amaya F, Hashimoto S, Ueno H, Beppu S, Mizuta M, Shime N, Ishizaka A, Hashimoto S. Acute lung inflammation and ventilator-induced lung injury caused by ATP via the P2Y receptors: an experimental study. Respir Res 2008; 9:79. [PMID: 19077288 PMCID: PMC2627837 DOI: 10.1186/1465-9921-9-79] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 12/13/2008] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Extracellular adenosine 5'-triphosphate (ATP) is an endogenous signaling molecule involved in multiple biological phenomena, including inflammation. The effects of extracellular ATP in the lung have not been fully clarified. This study examined 1) the biological roles of extracellular ATP in the pathogenesis of lung inflammation and 2) the possibility of involvement of extracellular ATP in mechanical ventilation-induced lung injury. METHODS The effects of intratracheal ATP on lung permeability, edema or lung inflammation were assessed by measurements of the lung wet-to-dry weight ratio and lung permeability index, immunohistochemistry and expression of key cytokines by real-time polymerase chain reaction. The ATP concentration in broncho-alveolar lavage (BAL) fluid from mice mechanically ventilated was measured by luciferin-luciferase assay. The suppressive effects of a P2 receptor antagonist on ventilator-induced lung inflammation were also examined. RESULTS ATP induced inflammatory reactions in the lung mainly via the ATP-P2Y receptor system. These reactions were alleviated by the co-administration of a specific P2 receptor antagonist. Mechanical ventilation with a large tidal volume caused lung inflammation and increased the ATP concentration in BAL fluid. P2 receptor antagonism partially mitigated the inflammatory effects of large tidal volume ventilation. CONCLUSION Our observations suggest that the ATP-P2Y receptor system is partially involved in the pathogenesis of ventilator-induced lung injury.
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Affiliation(s)
- Hiroki Matsuyama
- Department of Anesthesiology and Intensive Care, Kyoto Prefectural University of Medicine, Kyoto, Japan.
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Geiger RC, Kaufman CD, Lam AP, Budinger GRS, Dean DA. Tubulin acetylation and histone deacetylase 6 activity in the lung under cyclic load. Am J Respir Cell Mol Biol 2008; 40:76-82. [PMID: 18635817 DOI: 10.1165/rcmb.2007-0307oc] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Previous studies from our lab have demonstrated that upon exposure to physiologic levels of cyclic stretch, alveolar epithelial cells demonstrate a significant decrease in the amount of polymerized tubulin (Geiger et al., Gene Therapy 2006;13:725-731). However, not all microtubules are disassembled, although the mechanisms or implications of this were unknown. Using immunofluorescence microscopy, Western blotting, and immunohistochemistry approaches, we have compared the levels of acetylated tubulin in stretched and unstretched A549 cells and in murine lungs. In cultured cells exposed to cyclic stretch (10% change in basement membrane surface area at 0.25 Hz), nearly all of the remaining microtubules were acetylated, as demonstrated using immunofluorescence microscopy. In murine lungs ventilated for 20 minutes at 12 to 20 ml/kg followed by 48 hours of spontaneous breathing or for 3 hours at 16 to 40 ml/kg, levels of acetylated tubulin were increased in the peripheral lung. In both our in vitro and in vivo studies, we have found that mild to moderate levels of cyclic stretch significantly increases tubulin acetylation in a magnitude- and duration-dependent manner. This appears to be due to a decrease in histone deacetylase 6 activity (HDAC6), the major tubulin deacetylase. Since it has been previously shown that acetylated microtubules are positively correlated to a more stable population of microtubules, this result suggests that microtubule stability may be increased by cyclic stretch, and that tubulin acetylation is one way in which cells respond to changes in exogenous mechanical forces.
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Affiliation(s)
- R Christopher Geiger
- Division of Pulmonary and Critical Care Medicine, Northwestern University Medical School, Chicago, Illinois, USA
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Boost KA, Hoegl S, Dolfen A, Czerwonka H, Scheiermann P, Zwissler B, Hofstetter C. Inhaled levosimendan reduces mortality and release of proinflammatory mediators in a rat model of experimental ventilator-induced lung injury*. Crit Care Med 2008; 36:1873-9. [DOI: 10.1097/ccm.0b013e3181743e63] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Chiumello D, Carlesso E, Cadringher P, Caironi P, Valenza F, Polli F, Tallarini F, Cozzi P, Cressoni M, Colombo A, Marini JJ, Gattinoni L. Lung stress and strain during mechanical ventilation for acute respiratory distress syndrome. Am J Respir Crit Care Med 2008; 178:346-55. [PMID: 18451319 DOI: 10.1164/rccm.200710-1589oc] [Citation(s) in RCA: 463] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
RATIONALE Lung injury caused by a ventilator results from nonphysiologic lung stress (transpulmonary pressure) and strain (inflated volume to functional residual capacity ratio). OBJECTIVES To determine whether plateau pressure and tidal volume are adequate surrogates for stress and strain, and to quantify the stress to strain relationship in patients and control subjects. METHODS Nineteen postsurgical healthy patients (group 1), 11 patients with medical diseases (group 2), 26 patients with acute lung injury (group 3), and 24 patients with acute respiratory distress syndrome (group 4) underwent a positive end-expiratory pressure (PEEP) trial (5 and 15 cm H2O) with 6, 8, 10, and 12 ml/kg tidal volume. MEASUREMENTS AND MAIN RESULTS Plateau airway pressure, lung and chest wall elastances, and lung stress and strain significantly increased from groups 1 to 4 and with increasing PEEP and tidal volume. Within each group, a given applied airway pressure produced largely variable stress due to the variability of the lung elastance to respiratory system elastance ratio (range, 0.33-0.95). Analogously, for the same applied tidal volume, the strain variability within subgroups was remarkable, due to the functional residual capacity variability. Therefore, low or high tidal volume, such as 6 and 12 ml/kg, respectively, could produce similar stress and strain in a remarkable fraction of patients in each subgroup. In contrast, the stress to strain ratio-that is, specific lung elastance-was similar throughout the subgroups (13.4 +/- 3.4, 12.6 +/- 3.0, 14.4 +/- 3.6, and 13.5 +/- 4.1 cm H2O for groups 1 through 4, respectively; P = 0.58) and did not change with PEEP and tidal volume. CONCLUSIONS Plateau pressure and tidal volume are inadequate surrogates for lung stress and strain. Clinical trial registered with www.clinicaltrials.gov (NCT 00143468).
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Affiliation(s)
- Davide Chiumello
- Dipartimento di Anestesia, Rianimazione, Intensiva e Subintensivae, Terapia del Dolore, Fondazione IRCCS, Ospedale Maggiore Policlinico Mangiagalli Regina Elena di Milano, Milan, Italy.
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Otto CM, Markstaller K, Kajikawa O, Karmrodt J, Syring RS, Pfeiffer B, Good VP, Frevert CW, Baumgardner JE. Spatial and temporal heterogeneity of ventilator-associated lung injury after surfactant depletion. J Appl Physiol (1985) 2008; 104:1485-94. [PMID: 18323462 DOI: 10.1152/japplphysiol.01089.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Volutrauma and atelectrauma have been proposed as mechanisms of ventilator-associated lung injury, but few studies have compared their relative importance in mediating lung injury. The objective of our study was to compare the injury produced by stretch (volutrauma) vs. cyclical recruitment (atelectrauma) after surfactant depletion. In saline-lavaged rabbits, we used high tidal volume, low respiratory rate, and low positive end-expiratory pressure to produce stretch injury in nondependent lung regions and cyclical recruitment in dependent lung regions. Tidal changes in shunt fraction were assessed by measuring arterial Po(2) oscillations. After ventilating for times ranging from 0 to 6 h, lungs were excised, sectioned gravitationally, and assessed for regional injury by evaluation of edema formation, chemokine expression, upregulation of inflammatory enzyme activity, and alveolar neutrophil accumulation. Edema formation, lung tissue interleukin-8 expression, and alveolar neutrophil accumulation progressed more rapidly in dependent lung regions, whereas macrophage chemotactic protein-1 expression progressed more rapidly in nondependent lung regions. Temporal and regional heterogeneity of lung injury were substantial. In this surfactant depletion model of acute lung injury, cyclical recruitment produced more injury than stretch.
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Affiliation(s)
- Cynthia M Otto
- Departmrnt of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
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Pugin J, Dunn-Siegrist I, Dufour J, Tissières P, Charles PE, Comte R. Cyclic stretch of human lung cells induces an acidification and promotes bacterial growth. Am J Respir Cell Mol Biol 2007; 38:362-70. [PMID: 17921360 DOI: 10.1165/rcmb.2007-0114oc] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The reasons for bacterial proliferation in the lungs of mechanically ventilated patients are poorly understood. We hypothesized that prolonged cyclic stretch of lung cells influenced bacterial growth. Human alveolar type II-like A549 cells were submitted in vitro to prolonged cyclic stretch. Bacteria were cultured in conditioned supernatants from cells submitted to stretch and from control static cells. Escherichia coli had a marked growth advantage in conditioned supernatants from stretched A549 cells, but also from stretched human bronchial BEAS-2B cells, human MRC-5 fibroblasts, and murine RAW 264.7 macrophages. Stretched cells compared with control static cells acidified the milieu by producing increased amounts of lactic acid. Alkalinization of supernatants from stretched cells blocked E. coli growth. In contrast, acidification of supernatants from control cells stimulated bacterial growth. The effect of various pharmacological inhibitors of metabolic pathways was tested in this system. Treatment of A549 cells and murine RAW 264.7 macrophages with the Na(+)/K(+)-ATPase pump inhibitor ouabain during cyclic stretch blocked both the acidification of the milieu and bacterial growth. Several pathogenic bacteria originating from lungs of patients with ventilator-associated pneumonia (VAP) also grow better in vitro at slightly acidic pH (pH 6-7.2), pH similar to those measured in the airways from ventilated patients. This novel metabolic pathway stimulated by cyclic stretch may represent an important pathogenic mechanism of VAP. Alkalinization of the airways may represent a promising preventive strategy in ventilated critically ill patients.
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Affiliation(s)
- Jérôme Pugin
- Soins Intensifs, Hôpitaux Universitaires de Genève, 1211 Genève 14, Switzerland.
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Yang YL, Tang GJ, Wu YL, Yien HW, Lee TS, Kou YR. Exacerbation of wood smoke-induced acute lung injury by mechanical ventilation using moderately high tidal volume in mice. Respir Physiol Neurobiol 2007; 160:99-108. [PMID: 17964866 DOI: 10.1016/j.resp.2007.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 09/03/2007] [Accepted: 09/10/2007] [Indexed: 11/27/2022]
Abstract
We investigated the effects of mechanical ventilation with a moderately high tidal volume (VT) on acute lung injury (ALI) induced by wood smoke inhalation in anesthetized mice. Animals received challenges of air, 30 breaths of smoke (30SM) or 60 breaths of smoke (60SM) and were then ventilated with a VT of 10 ml/kg (10VT) or 16 ml/kg (16VT). After 4-h mechanical ventilation, the bronchoalveolar-capillary permeability, pulmonary infiltration of inflammatory cells, total lung injury score and pulmonary expressions of interleukin-1beta and macrophage inflammatory protein-2 mRNA and proteins in the 30SM+16VT and 60SM+16VT groups were greater than those in the 30SM+10VT and 60SM+10VT groups, respectively. Additionally, the wet/dry weight ratio of lung tissues and lung epithelial cell apoptosis in the 60SM+16VT group were greater than those in the 60SM+10VT group. These differences between the 16VT and 10VT groups were not seen in animals with air challenge. Thus, mechanical ventilation with a moderately high VT in mice exacerbates ALI induced by wood smoke inhalation.
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Affiliation(s)
- You-Lan Yang
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Miranda DR, Gommers D, Papadakos PJ, Lachmann B. Mechanical Ventilation Affects Pulmonary Inflammation in Cardiac Surgery Patients: The Role of the Open-Lung Concept. J Cardiothorac Vasc Anesth 2007; 21:279-84. [PMID: 17418750 DOI: 10.1053/j.jvca.2006.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Indexed: 11/11/2022]
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Chaturvedi LS, Marsh HM, Basson MD. Src and focal adhesion kinase mediate mechanical strain-induced proliferation and ERK1/2 phosphorylation in human H441 pulmonary epithelial cells. Am J Physiol Cell Physiol 2007; 292:C1701-13. [PMID: 17215324 DOI: 10.1152/ajpcell.00529.2006] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pulmonary epithelial cells are exposed to repetitive deformation during physiological breathing and mechanical ventilation. Such deformation may influence pulmonary growth, development, and barotrauma. Although deformation stimulates proliferation and activates extracellular signal-regulated kinases (ERK1/2) in human pulmonary epithelial H441 cells, the upstream mechanosensors that induce ERK activation are poorly understood. We investigated whether c-Src or focal adhesion kinase (FAK) mediates cyclic mechanical strain-induced ERK1/2 activation and proliferation in human pulmonary epithelial (NCI-H441) cells. The H441 and A549 cells were grown on collagen I-precoated membranes and were subjected to an average 10% cyclic mechanical strain at 20 cycles/min. Cyclic strain activated Src within 2 min by increasing phosphorylation at Tyr(418), followed by rapid phosphorylation of FAK at Tyr(397) and Tyr(576) and ERK1/2 at Thr(202)/Tyr(204) (n = 5, P < 0.05). Twenty-four (A549 cells) and 24-72 h (H441 cells) of cyclic mechanical strain increased cell numbers compared with static culture. Twenty-four hours of cyclic strain also increased H441 FAK, Src, and ERK phosphorylation without affecting total FAK, Src, or ERK protein. The mitogenic effect was blocked by Src (10 micromol/l PP2 or short interfering RNA targeted to Src) or MEK (50 micromol/l PD-98059) inhibition. PP2 also blocked strain-induced phosphorylation of FAK-Tyr(576) and ERK-Thr(202)/Tyr(204) but not FAK-Tyr(397). Reducing FAK by FAK-targeted short interfering RNA blocked mechanical strain-induced mitogenicity and significantly attenuated strain-induced ERK activation but not strain-induced Src phosphorylation. Together, these results suggest that repetitive mechanical deformation induced by ventilation supports pulmonary epithelial proliferation by a pathway involving Src, FAK, and then ERK signaling.
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Affiliation(s)
- Lakshmi S Chaturvedi
- John D. Dingell Veterans Affairs Medical Center, 4646 John R. St., Detroit, MI 48201, USA
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Cepkova M, Brady S, Sapru A, Matthay MA, Church G. Biological markers of lung injury before and after the institution of positive pressure ventilation in patients with acute lung injury. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2007; 10:R126. [PMID: 16956410 PMCID: PMC1751077 DOI: 10.1186/cc5037] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 08/14/2006] [Accepted: 09/06/2006] [Indexed: 12/28/2022]
Abstract
BACKGROUND Several biological markers of lung injury are predictors of morbidity and mortality in patients with acute lung injury (ALI). The low tidal volume lung-protective ventilation strategy is associated with a significant decrease in plasma biomarker levels compared to the high tidal volume ventilation strategy. The primary objective of this study was to test whether the institution of lung-protective positive pressure ventilation in spontaneously ventilating patients with ALI exacerbates pre-existing lung injury by using measurements of biomarkers of lung injury before and after intubation. MATERIALS AND METHODS A prospective observational cohort study was conducted in the intensive care unit of a tertiary care university hospital. Twenty-five intubated, mechanically ventilated patients with ALI were enrolled. Physiologic data and serum samples were collected within 6 hours before intubation and at two different time points within the first 24 hours after intubation to measure the concentration of interleukin (IL)-6, IL-8, intercellular adhesion molecule 1 (ICAM-1), and von Willebrand factor (vWF). The differences in biomarker levels before and after intubation were analysed using repeated measures analysis of variance and a paired t test with correction for multiple comparisons. RESULTS Before endotracheal intubation, all of the biological markers (IL-8, IL-6, ICAM-1, and vWF) were elevated in the spontaneously breathing patients with ALI. After intubation and the institution of positive pressure ventilation (tidal volume 7 to 8 ml/kg per ideal body weight), none of the biological markers was significantly increased at either an early (3 +/- 2 hours) or later (21 +/- 5 hours) time point. However, the levels of IL-8 were significantly decreased at the later time point (21 +/- 5 hours) after intubation. During the 24-hour period after intubation, the PaO2/FiO2 (partial pressure of arterial oxygen/fraction of the inspired oxygen) ratio significantly increased and the plateau airway pressure significantly decreased. CONCLUSION Levels of IL-8, IL-6, vWF, and ICAM-1 are elevated in spontaneously ventilating patients with ALI prior to endotracheal intubation. The institution of a lung-protective ventilation strategy with positive pressure ventilation does not further increase the levels of biological markers of lung injury. The results suggest that the institution of a lung-protective positive pressure ventilation strategy does not worsen the pre-existing lung injury in most patients with ALI.
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Affiliation(s)
- Magda Cepkova
- The Cardiovascular Research Institute and the Departments of Medicine and Anesthesia, University of California, San Francisco, 505 Parnassus Avenue, M917, San Francisco, CA 94143-0624, USA
| | - Sandra Brady
- The Cardiovascular Research Institute and the Departments of Medicine and Anesthesia, University of California, San Francisco, 505 Parnassus Avenue, M917, San Francisco, CA 94143-0624, USA
| | - Anil Sapru
- The Cardiovascular Research Institute and the Departments of Medicine and Anesthesia, University of California, San Francisco, 505 Parnassus Avenue, M917, San Francisco, CA 94143-0624, USA
| | - Michael A Matthay
- The Cardiovascular Research Institute and the Departments of Medicine and Anesthesia, University of California, San Francisco, 505 Parnassus Avenue, M917, San Francisco, CA 94143-0624, USA
| | - Gwynne Church
- The Cardiovascular Research Institute and the Departments of Medicine and Anesthesia, University of California, San Francisco, 505 Parnassus Avenue, M917, San Francisco, CA 94143-0624, USA
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Wright JL, Churg A. Commentary--Pathophysiology of airflow obstruction: could there really be an early test of prognostic significance? COPD 2006; 1:93-5. [PMID: 16997742 DOI: 10.1081/copd-120028704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This article represents a commentary on a controversial hyphothesis described by Dr.Milic-Emili in this issue. The authors discuss the hyphothesis and suggest that a re-examination of longitudinal lung function data could prove or deny his suggestion.
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Affiliation(s)
- J L Wright
- Department of Pathology, University of British Columbia, 2211 Wesbrook Mall, Room GF164, VGT 2B5, Vancouver, British Columbia, Canada.
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Birukova AA, Chatchavalvanich S, Rios A, Kawkitinarong K, Garcia JGN, Birukov KG. Differential regulation of pulmonary endothelial monolayer integrity by varying degrees of cyclic stretch. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 168:1749-61. [PMID: 16651639 PMCID: PMC1606576 DOI: 10.2353/ajpath.2006.050431] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ventilator-induced lung injury is a life-threatening complication of mechanical ventilation at high-tidal volumes. Besides activation of proinflammatory cytokine production, excessive lung distension directly affects blood-gas barrier and lung vascular permeability. To investigate whether restoration of pulmonary endothelial cell (EC) monolayer integrity after agonist challenge is dependent on the magnitude of applied cyclic stretch (CS) and how these effects are linked to differential activation of small GTPases Rac and Rho, pulmonary ECs were subjected to physiologically (5% elongation) or pathologically (18% elongation) relevant levels of CS. Pathological CS enhanced thrombin-induced gap formation and delayed monolayer recovery, whereas physiological CS induced nearly complete EC recovery accompanied by peripheral redistribution of focal adhesions and cortactin after 50 minutes of thrombin. Consistent with differential effects on monolayer integrity, 18% CS enhanced thrombin-induced Rho activation, whereas 5% CS promoted Rac activation during the EC recovery phase. Rac inhibition dramatically attenuated restoration of monolayer integrity after thrombin challenge. Physiological CS preconditioning (5% CS, 24 hours) enhanced EC paracellular gap resolution after step-wise increase to 18% CS (30 minutes) and thrombin challenge. These results suggest a critical role for the CS amplitude and the balance between Rac and Rho in mechanochemical regulation of lung EC barrier.
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Affiliation(s)
- Anna A Birukova
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois 60637, USA
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Marini JJ. Limitations of clinical trials in acute lung injury and acute respiratory distress syndrome. Curr Opin Crit Care 2006; 12:25-31. [PMID: 16394780 DOI: 10.1097/01.ccx.0000198996.22072.4a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW To review the challenges and limitations of randomized clinical trials in acute respiratory distress syndrome, with special emphasis on those pertaining to ventilatory management. RECENT FINDINGS Superbly executed randomized trials of ventilatory strategy have garnered deserved attention from the critical care community and yet have illustrated the limitations of our current approach to clinical research in this area. Inexact definitions, incomplete mechanistic understanding of complex pathophysiology, inappropriate outcome variables, diverse therapeutic environments, lengthy data acquisition time and ethical constraints on trial design limit the applicability of randomized control trial methodology to acute respiratory distress syndrome and acute lung injury. As yet, clinical practice does not seem to have been greatly impacted by the implications of completed randomized controlled trials per se. Recent issues, both ethical and interpretive, regarding control group participants have raised troubling and theoretically important issues that are yet to be fully resolved. SUMMARY Without tighter definitions of the condition under treatment, more specific targets for interventions to act upon, stratification that recognizes key interactive elements, and cointerventions based on better mechanistic understanding, randomized controlled trials of new drugs, ventilatory strategy, and other management approaches in acute respiratory distress syndrome are likely to remain a blunt instrument for investigation. As valuable as they are for calling important therapeutic principles to attention and for helping to suggest general guidelines for care, the limitations of randomized controlled trials for treating the individual with acute respiratory distress syndrome must be acknowledged.
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Affiliation(s)
- John J Marini
- University of Minnesota, Minneapolis/St Paul, Minnesota 55101, USA.
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Abstract
Patients with severe acute respiratory distress syndrome who die usually succumb to multiorgan failure as opposed to hypoxia. Despite appropriate resuscitation, some patients' symptoms persist on a downward spiral, apparently propagated by an uncontained systemic inflammatory response. This phenomenon is not well understood. However, a novel hypothesis to explain this observation proposes that it is related to the life-saving ventilatory support used to treat the respiratory failure. According to this hypothesis, mechanical ventilation per se, by altering both the magnitude and the pattern of lung stretch, can cause changes in gene expression and/or cellular metabolism that ultimately can lead to the development of an overwhelming inflammatory response-even in the absence of overt structural damage. This mechanism of injury has been termed biotrauma. In this review we explore the biotrauma hypothesis, the causal relationship between biophysical injury and organ failure, and its implications for the future therapy and management of critically ill patients.
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Affiliation(s)
- Claudia C dos Santos
- Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada.
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